A conventional power stapler is shown in FIG. 1 and includes a barrel 100 and a magazine 13 is connected to the barrel 100. A pushing member 11 is movably received in the magazine 13 by a spring means 12 so that the staplers 10 in the magazine 13 is pushed toward the barrel 100. In other words, the staplers 10 will be automatically fed to the barrel 100 one by one. A sliding member 101 is slidably mounted to the barrel 100 and actuates the ejecting mechanism of the power stapler to ready for next shoot. Therefore, the sliding member 101 will slide reciprocatingly along the barrel 100 if the user pulls the trigger continuously, and the upper-most stapler 10 in the magazine will be ejected by the ejecting member of the ejecting mechanism. The pushing member 11 has two protrusions 14 to catch the staplers 10 in the magazine 13. Nevertheless, when the last stapler is used out, the protrusions 14 will located in the barrel 100 and the ejecting mechanism still moves to hit the protrusion 14. This will damages the important mechanism of the power stapler.
The present invention intends to provide a safety device that prevent the pushing mechanism from moving when the last stapler runs out. The safety device in accordance with the present invention effectively resolves the inherent shortcoming of the conventional power stapler as described above.